And that's exactly where the city of Vienna hooks in. At the previous bikefestival I got this:
And this is for sure the best give-away I ever got! No pencil, ballpoint pen, magnet nor water bottle (not that I ever got one) can compete with that. What is it? It's a transparent, small and light one-way poncho for cycling. It has a perfect size for carrying around all the time. And that's what I do. No more rain pants and rain jackets. Just this tiny packet of plastic. And it works -- I've already thunderstorm-approved it in Barcelona :-). Although it's meant for single use I just let it dry, folded it and could even fit it in the small bag again. It got three packets (call me greedy if you want) which will probably last for years. Afterwards I will just buy a proper poncho.
Unstylish? I don't think so (unlike you choose the grandma model I suppose). Moreover, a poncho is light enough to carry around, cheap, easy and quick to put on and take off, can be worn with everything, covers the backpacks or other bags too, waterproof but pervious to air (no more sweating in rain pants), can serve as a picnic blanket and so on.
And for those who are still afraid of rain, let me tell you that you're not made of sugar and that there's nothing funnier than cycling in all kinds of weather. Sunshine and warmth is of course nice, but boring. You are just being lazy if you stick to only that -- and you probably haven't experienced the happiness after a ride in pouring rain yet. Or as we tend to say here:
There's no bad weather, just bad clothing.